Radon and Home Sales in Columbia, SC: What to Know

Most of the value talk around a house is about kitchens, curb appeal and how many bedrooms fit on a listing. The things that can slow a sale down are usually less glamorous. A home inspection finds a roof problem. An appraisal comes in low. And once in a while, a radon test comes back with a number nobody expected.

If you are buying or selling around Columbia, here is what is worth knowing before that happens.

What the Law Says About Radon When a House Changes Hands

South Carolina has a seller disclosure law, and radon is named in it. The state’s disclosure statute lists “radon gas” among the conditions the seller’s property condition disclosure statement has to address, alongside lead-based paint, asbestos, methane gas and underground storage tanks.

A few details matter in practice:

The law lets an owner mark that they make no representations about a particular condition, so a blank or a “no representation” answer is not the same as a clean bill of health.
Buyers keep their own duty to inspect the property. The statute says the disclosure rules do not limit that duty.
Some transfers are exempt, including foreclosures, estate administrations and transfers between family members, and sellers and buyers can also agree in writing to skip the form.
An owner who knowingly gives false, incomplete or misleading information can be liable for actual damages.

None of that tells you what your own house tests at. It only tells you the question is a real part of a South Carolina sale. For how it applies to your transaction, ask your agent or a real estate attorney.

What the Local Data Shows (and What It Can’t Tell You)

South Carolina’s radon program publishes average in-home results by county, built from the tests it has handled. The figures run through June 30, 2022, and cover first tests of homes that had not been mitigated before. The state notes it cannot guarantee that every kit was used under proper testing conditions.

For the Columbia area, the counts look like this:

County	Homes tested	Average result	Highest single result
Richland	1,468	1.0	46.4
Lexington	1,329	1.7	49.5
Kershaw	156	1.0	9.0

All of those are in picocuries per liter (pCi/L). The EPA’s recommended action level is 4.0 pCi/L.

Look at the first two columns and you might relax. Averages of 1.0 and 1.7 sit well under 4.0. Now look at the last column. Somewhere in Richland County, one home tested at 46.4. In Lexington County, one tested at 49.5. Those are more than eleven times the action level.

That is the whole point of testing a specific house. A county average is a blend of a lot of homes, and radon levels depend on the soil and rock under a particular lot, how the foundation was built and how air moves through the house. Two neighbors can get different answers. The average tells you the odds. Only a test tells you about your home.

Why a Test Result Shows Up in a Sale

Testing is common during a purchase, and it is easy to see why. It is inexpensive compared with most inspection items, it can be done without tearing anything apart, and it gives both sides a number instead of a guess.

If you are the one selling, the best time to find out is before a buyer does. A seller who already has a recent result in hand, and a plan if it is high, is in a calmer spot than one who learns it from the buyer’s inspector with a closing date on the calendar. A high number is a repair item. It is not a reason a house cannot sell.

If you are buying, ask whether the home has been tested and whether a system is already in place. A house with a working system and a documented result can be a good thing to find. It means someone already dealt with it.

How to Test Without Making a Mess of It

You can start simply. SCDES offers test kits through its radon program page, where you can request one online or by mail, and the page also points to a way to find a professional. The EPA’s radon page explains how and where to test.

A few habits make results more reliable:

Test in the lowest level of the home that people actually use.
Keep windows and exterior doors closed as the testing instructions describe, and do not run the test during unusual weather or construction.
Do not move the device or open the package early, and send it back promptly if it goes to a lab.
If the number is at or above 4.0 pCi/L, a second test or a professional’s confirmation is a sensible next step.

If a buyer’s inspector is doing the test, ask which method they are using and whether it is continuous or a passive kit. It is a fair question, and a good inspector will answer it without fuss.

If the Number Is High

A high result is a fixable one. Radon reduction is a known type of work, and the usual approach is to draw air from beneath the slab and vent it outside, with a fan and a pipe doing the job quietly in the background.

South Carolina does not license radon professionals, so it is worth asking any contractor for their credentials, such as certification through a national program like the NRPP or NRSB, and for references and a written scope before agreeing to anything. I run a directory of radon mitigation contractors in York, Pennsylvania, and the questions I ask there carry over to any state. If you want to know what a good contractor will do and how to read a quote, my walkthrough of what a radon mitigation job actually involves covers it from the first visit to the retest.

The key step after any fix is a follow-up test. It is the only way to confirm that the number came down.

The Takeaway for Sellers and Buyers

Radon is one line on a long inspection report, and it should not scare anyone off a good house. It should simply be on your list, early, with a real test instead of an assumption. The Columbia-area numbers show the pattern clearly: low averages, a few very high homes, and no way to know which one you own until you check.

Test first. Disclose honestly. Fix it if it needs fixing. Then get back to the part of the sale that is actually fun, like deciding what to put in that kitchen.